1. Field of the Invention
The present invention relates to an image processing system capable of displaying character information along with image and audio signals input through a set-top box in an image display, and a method for the same.
2. Description of the Related Art
Due to the development of data compression and transmission techniques, image processing systems capable of displaying image and audio data through wireless and wired interconnections are widely utilized. One example of such image processing systems includes a system combined with a set-top box which provides images as data streams in accordance with a Moving Picture Expert Group (MPEG) standard and an image display which displays the received data streams. MPEG standards are used as standards for compressing and transmitting moving pictures and MPEG standards such as MPEG 1, 2, and 4 are utilized or proposed. Very high compression effectiveness may be obtained by means of the MPEG standards, which allow images to be transmitted at a very low bit rate. Accordingly, MPEG standards are widely utilized in compressing the received image and audio signals in devices such as a set-top box.
FIG. 1 shows one example of conventional image processing systems combined with a set-top box and an image display. Referring to FIG. 1, the set-top box 110 receives, compresses, and transmits broadcast signals to the image display 120, which in turn decodes and outputs the broadcast signals. The broadcast signals are provided, for example, through an antenna or by cables or wired broadcast providers. When it is required to include character information in the broadcast signals, a broadcast station inserts the characters or simple graphics into the broadcast signals to be emitted and transmits them. In other words, the character information is inserted into the broadcast signals when it is required to inform all receivers of the broadcast signals such as news, forecast information, and traffic information.
In general, a caption broadcast including character information may be classified into an open caption type and a closed caption type based on a manner of displaying the characters on a screen. The open caption type allows anyone to see characters inserted into content such as news, video, movie, and so forth. On the other hand, the closed caption type can have characters seen or not seen which have been input to some of TV scan lines through electric waves and processed by a decoder. In addition, the caption broadcast may be classified into an on-line service and an off-line service. The on-line service allows a live broadcast to be written in shorthand in real time and output, and the off-line service outputs contents in response to a broadcast in progress by inserting captions into recorded tapes or inputting data such as scripts in advance.
However, when urgent situations happen at government and public offices and public places such as train stations or terminals, there exists a limitation in a conventional image processing system that informs people at the public places of the urgent situation. In other words, character information is transmitted to all service areas of the broadcast, so that it is not suitable for transmitting the character information to small areas. In addition, there is a limitation on transmitting character information in real time, because the subject that transmits the character information is not a manager of the government or public offices but the broadcast station, and it should input the character information using specific equipment, which in turn limits character information required to be input at a fast speed.